Latch-bolt structure



June 10, 1930. E. J. BAUME 1,762,499

LATCH BOLT STRUCTURE Filed Dec. 14, 1927 V INVENTOR.

l -fP HHLL Jnnss firwn BY W Z MW Q 30 /Z 28 M 24 ATTORNEYS Patented June 10, 1930 PATENT OFFICE EDWALL JAMES BAUME, OF SANTA MONICA, CALIFORNIA LATCH-BOLT STRUCTURE Application filed December 14, 1927. Serial No. 239,853.

This invention relates to improvements in door latches, and pertains particularly to a set having a latch operable from a turntable member such as a knob shaft or shank. The

g; primary objects of this invention are first, to provide a novel rollback mechanism; second, to provide a novel latch retainer mechanism to hold the latch bolt in protracted position and operable by a collar mounted to be roiotated about the knob shank; third, to provide a bolt having a shank housing the roll-back mechanism; and fourth, to provide a bolt having a shank with slots therein communicating with a boretherein, in which bore is is housed, a roll-back mechanism operable by a knob shaft extending through said slots.

It is desirable to have a unitary latch structure which may be embodied in mortise latches and be installed with a minimum of I cutting of the door and fitting. A still further object of this invention is to provide a door latch which for installation of the door requires only boring a recess into the edge of the door for reception of the latch casing and a cross bore for the knob shai't.

Other objects and advantages will be made fully apparent from the following specification considered in connection with the accompanying drawings, in which:

Fig. 1 is an edge view of afragment of a door showing my improved latch mounted therein; Fig. 2 is a section as seen upon the line 2-2 of Fig. 1 with the latch bolt in protracted position; Fig. 3 is a section similar to Fig. 2 showing the latch bolt retracted; Fig. 4 is a section as seen on the line 44: of Fig. 2; Fig. 5 is a section as seen on the line 5-5 of Fig. 4 and Fig. 6 is a perspective view of the roll-back cylinder.

Referring with more particularity to the drawing, a door is indicated by 10. The door is provided with a cylindrical bore which may be conveniently made by means of an auger. Extending transversely through the door and communicating with the bore 11 is a transverse bore 12 which may be made drilled by the same means. The bore 11 serves to receive the casing of the latch bolt and the bore 12 ermits the passage therethrough of the knob shaft. Opposite to bore 12 is a bore 13 to receive a bushing holding the lock pin. The edge of the door is recessed to receive a selvage plate.

The latch bolt structure comprises a hollow cylindrical shell 14 having at the end thereoi a selvage plate 15 with suitable holes for screws 16 to hold the casing in position. The selvage plate is provided with a flat side 17 for maintaining the latch bolt against turning and to provide a shoulder to limit the projection of the latch bolt. The latch bolt has a head 18 with theusual beveled outer face. The shank of the latch bolt is hollow providing a chamber tohouse the roll-back mechanism. The latch bolt isslidable within the casing shell and has at its outer end a transverse pin2l serving as an abutment. Resting against the pin is a washer 22. Intermediate the ends of the chamber is a washer 23. Between the washer and the head of the latch bolt is a compression spring 24 resting at one end against the head and at the other end against the washer 23. Disposed within the chamber and the shank isa rollback cylinder which is hollow and best shown in Fig. 5. This cylinder is split at diametrically opposite points along lines 25 and 26. Longitudinally extending. slots 27 and 28 are provided in the cylinder at opposite sides. The cylinder may be made of sheet metal and indented to provide racks 29 and 30. The sections of the cylinder are such that they may be moved axially with respect to one another. ithin the cylinder is a pinion 31 meshing with the racks. It is provided with a square bore through which extends a knob shaft 32. The knob shaft is mounted to be rotated in escutcheon plates 33 and 34 secured to opposite faces of the door, and mounted upon the shaft are knobs 35 and 36. i

It is obvious that upon turning the knob, the pinion 31 will be rotated causing the racks to be moved axially of the shank in relation to oneanother. This will cause expansion or contractiono'f the roll-back cylinder. Upon expansion of the roll-back cylinder, one rack presses against the washer and abutment at the inner end, and the other rack presses against the washer at the opposite end, thereby retracting the bolt. At the same time,

compression spring 24 will be compressed as shown in Fig. 3. There is a double action against the compression spring, that of the bolt head and the abutment moving toward each other. It is apparent that a large compression spring having a large amplitude of movement may be employed. I-Ieretofore, a difficulty experienced in latch bolts has been that of obtaining an operating spring of sufiicient strength and size to adequately operate the latch. Upon releasing the knob, the compression spring will expand and project the latch bolt, restoring the parts to the position shown in Fig. 2. I The bolt may be retracted without turning of the knob by pressure inwardly on the bolthead. This occurs when the door is closed, the keeper engaging the bevelface of the bolt head and pushing the bolt inwardly againstthe action of the compression spring.

For the purpose .oflocking the latch bolt in protractedposition, a pin 37 is provided. This pin is mounted in thebody of the escutcheon plate portion 34%, and is projectable into the, slot 27 of the .roll=b,ack cylinder and a corresponding. slot in the shankof the bolt. A slot 38v extends. along a portion of the periphery. of the pin and is engaged by a rib. The escutcheon plate 34, has; a hub 39 and rotatablymonntedon the-hub, is a collar 4L0. Inthe collar is. a semi cylindrical chamber dOff -having a rib 4:1 inclined to'the axis of the. knob shaft and, engaging the slot 38 in pinBT. The. pin 37 will be retracted or projected uponrotation of the collar. It-is obviousthatby rotating the collar to a predeternuned position, pin 87 will be projected into. a slot of the bolt'shank to holdthe latter against movement. The collar upon rotation in the opposite direction, will retract the pin and free the bolt, It willalso be apparent that a similar collar andpin may be. mounted upon the other side of the door. Thus, the latch maybe locked from either sidev of the dOQL Such double locking isdesirable in hotels, offices. and other places.

'What I claim is:-

I'. In a door latch structure, the combination, of a casing, a protractablelatch bolt having a, carryingframe at; its inner end, oppositely disposed abutmentmembers, one being fired to said frameand the. other slidable, therein, a spring intermediate thev slidabutment. and thehead of said bolt tending to separate them} a, roll-back actuator expansible axially to press against said abutments and move the latter to, and from each other, and means to operate said actuator.

2,v In a, door latch structure, the combination of a casing, a protractable latch bolt, a'carryingw frame at its inner end, oppositely disposed abutment members, one being fixed to said frameand the other slidable therein, a springintermediate the slidable abutment and the head of said bolt tending to separate them; a roll-back comprising a pair of racks and a pinion meshing with said racks whereby upon rotation of said pinion to move said racks outwardly in relation to one another, one of said racks will press against one of said abutments to move the abutments to and from each other. Y

8. In a door latch structure, the combination of a casing, a protractable latch bolt, a carrying frame at its inner end, oppositely disposed abutments, one being fixed to said frame and the other slidable therein, a spring intermediate the slidable abutment and the head of said bolt tending to separate them; a roll-back comprising a longitudinally split tube, each section of said tube having a rack, said racks being oppositely disposed to one another, a pinion between and in mesh with said racks, and meanstorotate said pinion.

4. In a door latch structure, acombination of a casing having a bore, a latch bolt having a tubular shank, there being oppositely disposed longitudinally extending slotsinsaid shank, a knob shaft extending transversely through said shank and slot, a roll-back within said shank operable bysaid shaft to protract and retract said bolt, alock pin projectable into one of said slots transversely of saidbolt tohold said bolt against retraction, a collar rotatable about said shaft, and an axially inclinedrib and slot connecting said pin and collar whereby rotation of said collar will effect projection andretraction of said pin.

5,. In adoor latch structure, the combination of a casing having a bore, a latchbolt having a head and a tubular shank slidable in the bore of said casing, there being oppositely disposed longitudinally extending slots in said shank,'oppositely disposed abutments one being fixedto said shank at its inner end and the other slidable in the bore of said shank, a compression spring intermediate the head of said bolt and the slidable abutment tending to separate them; a rollbackcomprising alongitudinally split tube disposed within said shank, eachsection, of said tube having 'alrack, the racks being oppositely disposed to one another, a pinion between and in mesh with said racks, a knob shaft extending transversely through said shank and said slot; a lock pin projectable into one of said slots transversely ofsaid bolt to hold said bolt against retraction, a collar rotatable .aboutfsaid shaft, and an axially inclined rib and slot connection between said pin and collar whereby rotation of said collar will efiect projection and retraction of said pin.

In witness that I claim the foregoing I havehereunto subscribed my name this 25th day of November, 1927.

EDWALL JAMES BAUME; 

